Filetype
Abstract in UndeterminedObservations of chemically peculiar (CP) stars have been conducted for decades and have revealed a variety of spectrum anomalies, most prominent among them are line enhancements of heavy elements. The earlier observations were limited to the optical region and the use of less sensitive detectors, yet are responsible for much of our current characterization of the CP star ph
Black holes exceeding a billion solar masses have been detected at redshifts greater than six. The rapid formation of these objects may suggest a massive early seed or a period of growth faster than Eddington. Here we suggest a new mechanism along these lines. We propose that in the process of hierarchical structure assembly, dense star clusters can be contracted on dynamical timescales due to the
We present a review of elemental abundances in the Milky Way stellar disk, bulge, and halo with a focus on data derived from high-resolution stellar spectra. These data are fundamental in disentangling the formation history and subsequent evolution of the Milky Way. Information from such data is still limited and confined to narrowly defined stellar samples. The astrometric Gala satellite will soo
Cosmological long-duration gamma-ray bursts (LGRBs) are thought to originate from the core collapse to black holes (BHs) of stripped massive stars. Those with sufficient rotation form a centrifugally supported torus whose collapse powers the GRB. We investigate the role of tidal locking within a tight binary as a source of the necessary angular momentum. We find that the binary orbit must be no wi
We recorded spectra of Ho II emitted by hollow-cathode lamps, using the ultraviolet Fourier transform spectrometer (FTS) at Lund Observatory and the 2-m FTS at the National Institute of Standards and Technology. The combined wavenumber coverage spans the interval from 8000 to 49 600 cm(-1) (12 500 to 2016 angstrom). We measured 303 lines in these spectra and used them to determine energies and hyp
Observationally, the galactic chemical evolution of sulphur shows a complex pattern. Some studies find no correlation between [S/Fe] and [Fe/H] at halo metallcities, which is typical for alpha -elements, others find [S/Fe] increasing towards lower metallicities, and still others find a combination of the two. Each scenario has different implications for the Galactic chemical evolution of sulphur.
When inspecting the currently known pulsar population one finds a velocity distribution which is in constrast to the galactic rotation curve. This has lead researchers to believe that the pulsars receive linear momentum (a kick) at the SN event which produces these. In this work we try and see what can be learned about these kicks by studying the existing double neutron star binary population. We
I den svenska straffrätten döms allvarligt psykiskt störda brottslingar i regel till rättspsykiatrisk vård istället för fängelse. Om brottet anses ha begåtts ”under påverkan av” den allvarliga psykiska störningen så kan domen förenas med beslut om särskild utskrivningsprövning, vilket innebär att förvaltningsrätten beslutar om utskrivning när den bedömer att individen inte längre har ett vårdbehovIn Swedish criminal law, ”severely mentally disturbed” (allvarligt psykiskt störda) criminals are usually sentenced to psychiatric care instead of prison. If the crime is deemed to have been committed “under the influence” of this mental disturbance, the sentence can be combined with a prescription for “special release inquiry” (särskild utskrivningsprövning). This means that an administrative cou
We present a list of 72 radial velocity member stars in the metal-rich globular cluster NGC5927. The radial velocities are based on multiepoch, multifibre spectra. We identify 46 RGB/HB stars and 26 turn-off stars that are radial velocity members in the cluster. This cluster is situated quite close to the disk and hence fore-and/or background contamination, especially in the outskirts of the clust
It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the
Den 1 januari 1981 trädde den första skatteflyktslagen i kraft. Sedan dess har det alltid funnits ett rekvisit i lagen som föreskrivit att dess tillämpning förutsätter att ett visst förfarande strider mot lagstiftningens grunder eller syfte. Detta rekvisit anses vara det mest svårtillämpade av rekvisiten i 2 § skatteflyktslagen samtidigt som det anses det vara det viktigaste då det knyter an till
Dust measurements have been obtained with the dust detector onboard the Galileo spacecraft inside a distance of about 60RJ from Jupiter (Jupiter radius, RJ = 71,492 km) during two periods of about 8 days around Galileo's closest approaches to Ganymede on 27 June and on 6 Sept 1996. The impact rate of submicrometer-sized particles fluctuated by a factor of several hundred with a period of about 10
Runt vår stjärna Solen kretsar åtta planeter, samt dvärgplaneter, kometer och asteroider. Människor har rest till (och gått på) Månens yta, medan våra grannplaneter har besökts av olika rymdsonder och robotar som har skickat tillbaka bilder och mätningar. Från dessa lär vi oss ständigt nya saker om solsystemets olika himlakroppar. I denna planetariumvisning tar vi oss ut i rymden, reser bland plan
After graduation Willam have been able to make a career with numerous positions within the UK government, before transitioning over to the tech sector. This interview was made 2024.
https://www.iac.lu.se/transmigration-wisdome - 2026-05-27
E-waste is a growing waste problem around the world, and Sweden is no exception. However, the Swedish WEEE system is having issues combating the problem – particularly when it comes to cellphones. The aim of this research is to develop an understanding of the Swedish WEEE system in practice when it comes to cellphones, to explore what benefits actors in the Swedish system reap from choices to repa
Det är numera allmänt vedertaget att 80% av materian i universum består av en ny sorts partiklar som inte strålar eller interagerar med ljus. Med andra ord, den är ”mörk”. Vi känner redan till en slags ”mörk” partikel - neutrinon. Alla partiklar som är elektriskt oladdade är ”mörka”, men mörk materia kan inte huvudsakligen bestå av neutriner. Mörk materia verkar bestå av partiklar som är myckeWIMPs, orWeakly InteractingMassive Particles, are a popular dark matter candidate, but their detection remains elusive. At its core, this project is an effort to bridge the gap between the theory of WIMPs, and astronomical observation. According to the WIMP model, stars in the galaxy travel through a background field of WIMPs that are constantly crossing the star. Some of these WIMPs collide with
One of the mysteries of nebulae in the vicinity of bright stars is theappearance of bright emission spectral lines of ions, which imply fairlyhigh excitation temperatures. We suggest that an ion formationmechanism, based on resonance-enhanced two-photon ionization (RETPI) byintense H Lyman alpha radiation (wavelength of 1215 angstroms) trappedinside optically thick nebulae, can produce these spect
Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes we present detailed elemental abundances for 64 red giant stars in the inner and outer Galactic disk. For the inner disk sample (4-7 kpc from the Galactic centre) we find that stars with both thin and thick disk abundance patterns are present while for Galactocentric distances beyond 10 kpc, we only fin
Book abstract: The book reviews recent observations of non-evolved and evolved binary populations in clusters and the field with special emphasis on statistical biases, incompleteness and distribution functions. Different binary types are considered: cataclysmic variables, super-soft X-ray sources, double degenerate binaries, Algol-type binaries, Be binaries, X-ray binaries, and Wolf-Rayet binarie
